Friday, February 15, 2013

Changes in Arctic and Antarctic Ice Area Do Not Affect the Global Mean Temperature

Steven Goddard has a post stating that changes in the Antarctic sea ice area affect the shortwave (SW) radiation reaching the surface from the Sun, thus suggesting that could contribute to global warming or cooling. This of course assumes that the atmosphere is warmed, at least partially, by heat from the solar-warmed surface; virtually all scientists today believe this. The following is my response:In my seminal Venus/Earth temperatures comparison, that temperature ratio is a constant--at points of equal pressure in the two atmospheres, and over the range of Earth tropospheric pressures--which is precisely explained by the ratio of their distances from the Sun, and nothing else: No CO2 greenhouse effect (Venus's atmosphere has 96.5% CO2, Earth only 0.04%); no albedo effect (Venus's albedo is 0.7 or more, Earth's only 0.3); no surface effect (Venus's surface is all solid crust, Earth's 71% ocean).The reason why the Venus/Earth temperature ratio depends only upon the solar distances, is because both tropospheres--in the above-stated range of pressures--MUST be warmed by incident solar radiation, not from the surface (in fact, they must both absorb the same physical fraction of the incident solar radiation). So the Venus/Earth comparison, as properly done by me over 2 years ago, not only disproves the hypothesis that increasing atmospheric CO2 increases the global mean surface temperature, it also revolutionizes science's understanding of how the Earth atmosphere is warmed--just like all the other planetary atmospheres, it is warmed by direct absorption of incident solar radiation. That direct warming by the Sun is distributed according to the essentially hydrostatic, vertical pressure gradient--pressure increasing with depth in the atmosphere, and thus temperature increasing with depth (the negative lapse rate structure, which is clearly the stable, predominant condition determining the temperatures in the troposphere, according to the Standard Atmosphere model, used in and confirmed by my Venus/Earth analysis).And because the surface does not warm the atmosphere, except locally and transiently, changes in the reflectivity of the Earth's surface, as well as changes in the cloud cover, do NOT affect the ruling lapse rate structure or the global mean temperature.